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Biomedical subjects

R Chatterjee

Publications and source records attributed to R Chatterjee.

At least 73 records · Page 4Linked to original sources
PubMed1994

Germ cell failure and Leydig cell insufficiency in post-pubertal males after autologous bone marrow transplantation with BEAM for lymphoma.

Thirteen post-pubertal male patients aged 17-25 years were assessed for pituitary-gonadal function 0-3 months prior to and 2-3 months post-bone marrow transplantation for haematological malignancy. All patients had multiagent cytotoxic treatment prior to transplantation and 30% were found to have germ cell dysfunction with abnormal semen parameters before high-dose therapy indicating damage to the germinal epithelium. They also had evidence of reduced Leydig cell reserve even before transplantation. During transplantation all patients sustained sustained gonadal injury, the effect on their germ cells being more pronounced than on the Leydig cells. Fifty per cent had reduction in testicular volume and all had azoospermia 2-3 months post-transplantation. Our results indicate that short-term chemoradiotherapy causes profound damage to the germ cell compartment of the testis, with less severe damage to the Leydig cells, but no overt injury to the anterior pituitary gland. The changes appeared to be identical in patients conditioned with total body irradiation-based protocols and those who received only high-dose chemotherapy prior to bone marrow transplantation.

Adolescent↗
PubMed1994

Prevalence of serum IgG and IgM antibodies against Epstein-Barr virus capsid antigen in Indian patients with respiratory tract carcinomas.

Antibodies against Epstein-Barr virus capsid antigen (EBV-VCA) were measured in sera of Indian patients with respiratory tract carcinomas (lung, larynx, laryngopharynx, nasopharynx) using a commercial enzyme linked immunosorbent assay (ELISA) kit. Nineteen out of thirty-three (19/33) lung cancer, 12/22 laryngeal cancer, 11/16 laryngopharyngeal cancer, 6/9 nasopharyngeal carcinoma cases and 3/29 matched controls were positive for IgG antibody to VCA. None were positive for the IgM antibody to VCA. The antibody positivity was evaluated on the basis of immune status ratio (ISR) of the sera as described in the manual of the kit. Prevalence of the antibody was more pronounced among smokers with laryngeal and laryngopharyngeal carcinoma than among lung cancer cases. The results indicated that the antibody positivity rate among the patients declined with the advanced stages of the diseases. Serum IgG and IgM levels were raised in the patients who were tested positive for the viral antibody.

Adolescent↗
PubMed1993

Dinitrogenase reductase- and MgATP-dependent maturation of apodinitrogenase from Azotobacter vinelandii.

The requirements for iron-molybdenum cofactor (FeMo-co) activation of apodinitrogenase from Azotobacter vinelandii strain UW97, which lacks dinitrogenase reductase activity as assayed by substrate reduction, have been examined. Activation of apodinitrogenase from strain UW97 by FeMo-co requires the addition of both dinitrogenase reductase and MgATP. When the same apodinitrogenase is pretreated with dinitrogenase reductase and MgATP and then partially purified, however, it does not require these components for activation by FeMo-co. This suggests that dinitrogenase reductase and MgATP are involved in processing apodinitrogenase to a FeMo-co activatable form. This processing step coincides with a change in the subunit composition of apodinitrogenase from alpha 2 beta 2 to a form with an additional subunit (gamma) attached. The apodinitrogenase with the associated gamma subunit is apparently the form of the protein that is competent for activation by FeMo-co.

Adenosine Triphosphate↗
PubMed1993

Correlation of mitotic abnormalities and the presence of human papillomavirus antigens in squamous cell carcinomas of the oral cavity.

To determine the association of human papillomavirus (HPV) with oral cancer lesions containing abnormal mitoses, we analysed 54 of them by immunohistochemical techniques for the presence of HPV structural antigens and correlated the results with their histology. Sixteen out of 19 lesions with abnormal mitotic figures (MFs) and 15 of the 25 lesions with normal MFs contained the HPV antigen. However, 9 of the 11 koilocytotic lesions with abnormal MFs and 13 of the 17 lesions with normal MFs were HPV antigen-positive. The nature of mitosis was not influenced by the grades of koilocytosis. No correlation of HPV antigen positivity and severity of the oral carcinomas was observed.

Adult↗
PubMed1993

Effect of dexamethasone on the peptic activity of gastric lumen and mucosa.

Dexamethasone (9 alpha-fluoro-16 alpha methyl-11 beta,17 alpha,21-trihydroxy-1,4-pregnadiene-3,20-dione-21-phosphate), a synthetic glucocorticoid, has a dual role on pepsinogen content of the gastric lumen and mucosa as measured by its peptic activity. Following stimulation the luminal peptic activity gradually decreases after 6 hr, then returns to basal levels at 18 hr and by 24 hr is inhibited by 50%. The luminal peptic activity induced by the secretory compound mercaptomethylimidazole (MMI) is also decreased. Dexamethasone effect on both basal and MMI-induced peptic activity can be reproduced by cycloheximide or puromycin, translational blockers of protein synthesis. This drug also has an independent time and dose-dependent inhibitory effect on gastric mucosal peptic activity which does not correlate with increased peptic activity of the lumen. Dexamethasone appears to be more effective than hydrocortisone and corticosterone in inhibiting the basal peptic activity of both lumen and mucosa. The inhibitory effect of this drug on tissue peptic activity is not mediated through induction of any inhibitory protein as evidenced by the insensitivity of the effect to actinomycin D. Studies on [14C]phenylalanine incorporation into gastric protein indicate that the effect of dexamethasone on tissue pepsinogen content is not due to a generalized block of protein synthesis.

Animals↗
PubMed1993

Inhibition of intestinal peroxidase activity by nonsteroidal antiinflammatory drugs.

The peroxidase activity of the mitochondrial fraction of rat intestine is inhibited in vitro by non-steroidal antiinflammatory drugs (NSAIDs), such as indomethacin (IMN) and acetylsalicylic acid (ASA), the former being more potent than the latter. The peroxidase was solubilised by cetab-NH4Cl extraction and purified to apparent homogeneity by Sephadex G-150 gel filtration and affinity chromatography on Con-A Sepharose. The purified enzyme activity was 80% inhibited by 150 microM IMN and 50% by 2.67 mM ASA. IMN could also inhibit lactoperoxidase activity to the same extent but not the horseradish peroxidase activity. The inhibition of peroxidase-catalysed iodide oxidation by IMN and ASA was optimal at pH 5.5 and 4.5, respectively. Kinetic studies revealed that the inhibition by IMN was competitive with respect to iodide or guaiacol, while the inhibition by ASA was noncompetitive and reversible in nature. Studies of some structural analogues showed that indole-3-acetic acid was as effective as IMN, while salicylic acid was more potent than ASA. Spectral studies showed a small bathochromic shift of the Soret band of the enzyme by IMN, suggesting its possible interaction at or near the heme moiety. The competitive nature of IMN may be explained as due to its oxidation by the peroxidase to a product absorbing at 412 nm, the formation of which is inhibited by iodide. We suggest that IMN inhibits intestinal peroxidase activity by acting as a competitive substrate for the enzyme. As intestinal peroxidase is mainly contributed by the invading eosinophils, NSAIDs may affect the host defence mechanism by inhibiting the activity of the enzyme.

Animals↗
PubMed1993

Iodide modulation of the EDTA-induced iodine reductase activity of horseradish peroxidase by interaction at or near the EDTA-binding site.

Horseradish peroxidase (HRP) catalyses the reduction of iodinium ion (I+) to iodide by H2O2 in the presence of EDTA. I+ reduction occurs optimally at pH 6 whereas the enzyme catalyses iodide oxidation optimally at pH 3.5. Thus the two activities reside on the same enzyme with two characteristic pH optima. Iodide modulates the expression of the reductase activity by EDTA. Higher concentrations of iodide inhibit the reductase activity by EDTA. Nitrite, an electron donor, acts similarly to iodide. Both EDTA and nitrite competitively inhibit iodide oxidation, indicating that they compete with iodide for the same binding site for electron flow to the haem iron group. However, unlike iodide, EDTA converts compound I, not into the native enzyme, but into a compound absorbing at 416 nm which reduces I+ and then returns to the native form. The apparent equilibrium dissociation constant, KD, for the formation of the EDTA-HRP complex (15 mM) is doubled in the presence of iodide, indicating interference with EDTA binding by iodide. EDTA binds away from the haem iron centre and not through intramolecular Ca2+. The pH-dependence of EDTA binding indicates that an ionizable group of the enzyme with pKa 5.8, presumably a distal histidine, controls the binding. The data suggest that iodide competes with EDTA for compound I and modulates the iodine reductase activity by limiting the formation of the 416 nm-absorbing active compound.

Anions↗
PubMed1993

Smoking cessation interventions for university students: recruitment and program design considerations based on social marketing theory.

BACKGROUND: Audience variables with social marketing implications for university campuses were investigated to identify prepromotional campaign strategies for the design of smoking cessation interventions and for subject recruitment. METHODS: A first survey based on a stratified systematic probability sample of 2,998 college students at a large midwestern university identified 313 smokers. A total of 263 (response rate = 84%) participated in a second telephone survey, and results were based on the 193 (73%) respondents who still smoked. RESULTS: Recruitment implications indicate that potential participants are predominantly lower classmen in their early 20s who are unmarried, childless, white, full-time domestic students. Smoking habits are moderate but well-established and confined almost exclusively to cigarette smoking. An average of three attempts to quit smoking was reported, and the majority of respondents rated their interest and intention to quit as "somewhat" to "very likely." The best publicity options for programs are campus newspapers as well as grocery stores and gas stations, where most cigarettes are purchased. Program design implications suggest that accessibility, affordability, convenience, flexibility, social support, and behavioral prompts/cues are important factors to consider. CONCLUSIONS: This study is a first initiative to "fill the gap" in the social marketing research literature by providing recruitment and program design information specifically for developing a smoking cessation campaign for university campuses.

Adolescent↗
PubMed1993

Evaluation of growth hormone in thalassaemic boys with failed puberty: spontaneous versus provocative test.

Growth hormone (GH) secretion was determined by evaluating ultradian GH profiles for 12 h and GH responses to insulin stimulated hypoglycaemia (ITT) in 28 stunted boys with beta-thalassaemia major aged 15.2-17.4 years, who presented with pubertal failure (FP). Healthy non thalassaemia prepubertal boys (n = 10) aged 7.5-8.8 years, were studied as controls. All patients had normal responses to ITT with peak GH levels > or = 15 mU/l. Basal GH concentrations (mean +/- sem) (1.65 +/- 0.03 mU/l vs 2.58 +/- 0.27 mU/l; P < 0.05) and the stimulated GH responses (peak GH = 15.4 +/- 0.20 mU/l vs 21.08 +/- 0.78 mU/l; P < 0.001) were significantly lower in the patients with failed puberty than in the controls, indicating that the FP patients had diminished GH reserve and secretory capacity. Moreover, all the GH peak parameters including the maximum spontaneous concentrations (MX-GH) and the area under the GH curve (AUC) were significantly lower in the thalassaemic patients than in the controls (MX-GH = 5.2 +/- 0.21 mU/l vs 20.42 +/- 0.14 mU/l; P < 0.001; AUCb = 421.22 +/- 4.31 mU/l vs 712.20 +/- 3.42 mU/l; P < 0.001). These observations suggest that the thalassaemic patients had endogenous neurosecretory GH deficiency (GHND). Priming with sex steroid did not cause any improvement in the spontaneous or stimulated GH secretory patterns in thalassaemic patients. It was noteworthy that in neither the patients nor the control subjects, was there a significant correlation between the maximum stimulated and the MX-GH concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Prospective study of the hypothalamic-pituitary axis in thalassaemic patients who developed secondary amenorrhoea.

OBJECTIVE: We aimed to prospectively evaluate during 10 years the GnRH-gonadotrophin secretory dynamics in a cohort of 15 menstruating girls with beta-thalassaemia major to determine whether they sustained progressive damage to this axis. DESIGN: Patients were characterized by 12-hour gonadotrophin profiles (by sampling blood at 15-minute intervals) and assessment of gonadotrophin responses to 100 micrograms GnRH bolus (by sampling blood at 20-minute intervals for 1 hour and at 2 hours) sequentially during the follicular and luteal phases of their menstrual cycles, 12-14 months and 5-6 years after the onset of secondary amenorrhoea. SUBJECTS: We studied 15 post-menarcheal thalassaemic girls and five age-matched control subjects who were the healthy siblings of the patients. MEASUREMENTS: FSH and LH assays were determined using commercial RIA systems and double antibody techniques. Pulse detection used the Pulsar technique of Merriam and Wachter. RESULTS: We demonstrated that during their amenorrhoeic period, all thalassaemic patients had gonadotrophin pulse abnormalities and low-normal GnRH-stimulated gonadotrophin levels indicating that they had GnRH-gonadotrophin secretory insufficiency. During the subsequent 10 years there was progressive deterioration of hypothalamic-pituitary function in all patients; 66% became apulsatile and all had marked reduction in their GnRH-stimulated gonadotrophin levels. CONCLUSIONS: Our investigation suggests that thalassaemic patients with secondary amenorrhoea had severe and progressive damage to their hypothalamic-pituitary axes despite intensive chelation therapy.

Adolescent↗
PubMed1993

Induction of ovarian function by using short-term human menopausal gonadotrophin in patients with ovarian failure following cytotoxic chemotherapy for haematological malignancy.

Currently no treatment has proved successful in inducing ovarian steroidogenic and/or gametogenic recovery in patients with haematological malignancies treated by cytotoxic chemotherapy once biochemical failure becomes manifest i.e., when FSH levels exceed 40 IU/L. This paper reports two such cases with classical biochemical ovarian failure in which ovarian function was induced by brief stimulation with Human Menopausal Gonadotrophin (HMG).

Adult↗
PubMed1992

Localization of gastric peroxidase and its inhibition by mercaptomethylimidazole, an inducer of gastric acid secretion.

Mercaptomethylimidazole (MMI) is a potent inducer of gastric acid secretion which is associated with significant inhibition of peroxidase activity of rat gastric mucosa in vivo. A time-dependent increase in acid secretion correlates well with time-dependent decrease in the peroxidase activity. In a chamber experiment in vitro using isolated gastric mucosa, MMI stimulates acid secretion, showing an almost linear response up to 600 microM. The time-dependent increase in acid secretion is also correlated with time-dependent inhibition of the peroxidase activity. This effect is not mediated through oxidation of MMI by flavin-containing mono-oxygenase, which is absent from gastric mucosa. The peroxidase has been localized mainly in parietal cells isolated and purified from gastric mucosa by controlled digestion with collagenase followed by Percoll-density-gradient centrifugation. Peroxidase activity was further localized in the outer membrane of the purified mitochondria of the parietal cell by some membrane-impermeant reagents, indicating outward orientation of the enzyme. MMI can inhibit the peroxidase activity of both the parietal cell and its mitochondria in a concentration-dependent manner. The possible involvement of the parietal-cell peroxidase-H2O2 system in MMI-induced acid secretion may be suggested.

4-Chloromercuribenzenesulfonate↗
PubMed1992

Lower respiratory tract infection in hospitalized children due to respiratory syncytial (RS) virus during a suspected epidemic period of RS virus in Delhi.

A study of 131 children below 5 years of age seeking hospitalization due to lower respiratory tract infections (LRTI), comprising 56 cases of bronchiolitis, 61 cases of bronchopneumonia, and 14 cases of other lower respiratory tract diseases showed significant occurrence of bronchiolitis in younger age groups (chi 2 = 79.21; P less than 0.001). Employing two rapid techniques, viz. immunofluorescent antibody technique (IFAT) and enzyme immunoassay (EIA) along with tissue culture, Respiratory Syncytial (RS) virus could be detected in higher percentage of bronchiolitis cases (54 per cent by both culture and IFAT, 70 per cent by EIA) compared to bronchopneumonia (36 per cent by both culture and IFAT, 49 per cent by EIA) and other LRTI cases (14 per cent each by culture, IFAT and EIA). The detection rate of RS virus was higher in the age group 0-6 months compared to the remaining age groups combined (7-60 months) in bronchiolitis cases irrespective of the technique employed while no such difference could be noted in bronchopneumonia. Eighteen (90 per cent) out of 20 specimens positive for RS virus by EIA, but negative by culture were found to be true positives as revealed by blocking test. In comparison to culture, sensitivities of IFAT, EIA, and EIA (by blocking test) were found to be 89, 94, and 94 per cent, respectively, while specificities of these techniques were found to be 92, 74, and 76 per cent, respectively. Higher detection rate of RS virus in the present study compared to earlier ones from India is attributed to application of EIA as well as selection of LRTI cases during a period of suspected epidemic of RS virus.

Age Factors↗
PubMed1992

How little luteal tissue of rats is needed to maintain pregnancy till term--an experimental verification.

Surgical reduction of luteal tissue to about 20% of its total mass on day 5 pc was found to maintain gestation till term. A high degree of fetal loss was, however, evident. An identical surgical manipulation at the end of maximal luteal maturity, that is, on day 16 pc, resulted in normal maintenance of gestation. Fetal growth and their survival rate were found to be comparable to controls. An exclusive surgical extirpation of corpora lutea, on the other hand, either on day 16, 17, 18 or 19 was found to cause 100% fetal loss by day 23. However, progesterone replacement therapy concurrently with surgical luteal ablation till day 20, or surgical extirpation of the entire luteal mass when shifted on day 20, led the pregnancy to term. Present experimental findings, therefore, suggest that only about 20% of the functionally matured luteal mass until day 20 is essentially enough to maintain an ideal pregnancy status till term.

Animals↗